High speed fiber optical systems may be used in various communication applications, for instance in telecommunication over long transmission distances. A telecommunication network may be classified into various levels such as subscriber networks, regional networks and national networks. The national networks, for example, may exist between different cities where there is a greater demand for higher transmission speeds above 10 gigabits/sec such as, for example, 25 gigabits/sec, 40 gigabits/sec or 100 gigabits/sec. In the national networks, for example, dispersion may limit the transmission speeds between transmitters and receivers. Optical dispersion is a fundamental problem for high-speed gigabit networks and is of particular importance as bit rates exceed 2.4 gigabits/sec, for example. In high volume 10 GbE ports based on, for example, a form-factor pluggable architecture, the settings of a pre-emphasis filter may be manually configured.
Intersymbol interference (ISI) may occur in digital communications in bandwidth-limited links. The main source of ISI in a fiber-optic system is signal pulse broadening due to fiber dispersion. There may be various types of dispersion in a fiber-optic system, which may comprise modal dispersion, chromatic dispersion and polarization mode dispersion, for example. In a multimode fiber, different mode groups have different velocities, which may be called modal dispersion. Chromatic dispersion may be caused by different wavelengths of light having different velocities. The polarization mode dispersion, which may be due to different velocities of different polarizations, may be neglected in multimode fibers. Dispersion is usually time varying due to environmental change such as temperature variation and is related to fiber length and/or bit rates. For example, a printed circuit board (PCB) trace loss for a 25-gigabit (Gb) signaling may be twice of that for a 10-gigabit (Gb) signaling. Higher PCB trace loss may introduce more dispersion variations.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with the present invention as set forth in the remainder of the present application with reference to the drawings.